Poor air qualityin Hong Kong

Reasons:
1. Over-consumption of fossil fuels, e.g. many vehicles driving in HK, electricity production etc, which produces pollutants such as sulphur dioxide and nitrogen oxides.
2. Deforestation, actually occurs mainly in tropical forest which the timbers are used for economic purpose. Less trees trap carbon dioxide and release oxygen, posing a poor air quality not just in HK, but also the whole globe.
3. Frequent fires burning in Autumn with concentrated fine particulates, also contribute to the poor air quality in HK.
4. Hongkongers who have smoking habit is also responsible for the poor quality in HK, as tobacco burns with toxic carbon monoxide and some other particulates, e.g. ashes which are carcinogenic.